Giant Cell Arteritis refers to the inflammation of the medium-to-large blood vessels that supply oxygen and nutrients to the head, neck, and arms. This condition is commonly referred to as temporal arteritis, as it often affects the temporal artery, causing headaches and jaw pain. However, there are several other synonyms used to describe this condition, including cranial arteritis, Horton's disease, and granulomatous arteritis. These terms all describe the same inflammatory condition, and diagnosis is made through a combination of symptoms, physical examination, and blood tests. Early diagnosis and treatment are essential, as Giant Cell Arteritis can lead to significant complications if left untreated.